Generally, an electrical connector for electrically connecting an electronic card is typically provided with a detection switch so as to judge whether the electronic card has been inserted. A detection switch in prior art typically comprises a fixed terminal and a resilient terminal, the fixed terminal and the resilient terminal are fixed to a housing (which is formed of an insulative material), and the resilient terminal partially extends into a slot of an electrical connector, and the resilient terminal is pushed by the electronic card inserted into the slot so as to change a contact state between the resilient terminal and the fixed terminal, and thus the detection switch can detect whether the electronic card has been inserted into the slot.
When the electronic card is not inserted into the slot, the resilient terminal and the fixed terminal contact each other, which is referred to as a normal close, or the resilient terminal and the fixed terminal are separated from each other, which is referred to as a normal open. Here, as for the normal close, the resilient terminal and the fixed terminal will be separated from each other when the electronic card has been inserted into the slot; as for the normal open, the resilient terminal and the fixed terminal will contact each other when the electronic card has been inserted into the slot.
Because only the resilient terminal with respect to the normal close has a predetermined preloaded force, a stable contact between the resilient terminal and the fixed terminal can be maintained. However, if the preloaded force exerted on the fixed terminal by the resilient terminal is too small, a poor connection will occur; if the preloaded force exerted on the fixed terminal by the resilient terminal is too large, the preloaded force will be transferred to the housing, which can cause the housing to warp after passing through reflow. If the preloaded force is exerted on a position of terminals close to a soldering region, coplanarity of soldering portions of the terminals can be affected.